54 HOMOPTEEA. 



a. Antennfe very variable in form, placed beneath 



the eyes, usually of two joints terminated by 

 a very fine hair. 

 a', Prouotum neither armed nor unusually 



developed Fulgoridae. 



c. Ocelli placed between the eyes. 



b. Antennae inserted in front of and between eyes. 

 a^. Pronotum prolonged backwards into a hood 



or process of variable form Membracidae. 



d. Ocelli (occasionally absent) placed on vertex. 



a^. Pronotum not prolonged beyond base of 

 abdomen. 



c. Posterior tibiae armed with one or two spines, 



and with a cluster of spinules at apex Cercopidae. 



e. Ocelli placed on front margin of head, usually 



almost in a line with front of eyes. 



d. Posterior tibi-e with a double series of spines 



beneath Jassidae. 



